Search Publications
The mass function of the Arches cluster from Gemini adaptive optics data
Brandner, W.; Grebel, E. K.; Stolte, A. +1 more
We have analysed high resolution adaptive optics (AO) science demonstration data of the young, massive stellar cluster Arches near the Galactic Center, obtained with the Gemini North telescope in combination with the University of Hawai'i AO system Hokupa'a. The AO H and K' photometry is calibrated using HST/NICMOS observations in the equivalent f…
Star formation and dust extinction in nearby star-forming and starburst galaxies
Buat, V.; Boselli, A.; Gavazzi, G. +1 more
We study the star formation rate and dust extinction properties of a sample of nearby star-forming galaxies as derived from Hα and UV ( ~ 2000 Å) observations and we compare them to those of a sample of starburst galaxies. The dust extinction in Hα is estimated from the Balmer decrement and the extinction in UV using the FIR to UV flux ratio or th…
Extragalactic globular clusters in the near-infrared. II. The globular clusters systems of NGC 3115 and NGC 4365
Minniti, D.; Hilker, M.; Kissler-Patig, M. +3 more
We combine near-infrared photometry obtained with the VLT/ISAAC instrument and archival HST/WFPC2 optical images to determine VIK magnitudes and colours of globular clusters in two early-type galaxies, NGC 3115 and NGC 4365. The combination of near-IR and optical photometry provides a way to lift the age-metallicity degeneracy. For NGC 3115, the g…
The FIR/Radio correlation of high redshift galaxies in the region of the HDF-N
Garrett, M. A.
The correlation between the far-infrared (FIR) and radio emission is well established for nearby star forming galaxies. Many applications, in particular the radio-to-submm spectral index redshift indicator, tacitly assume that the relation holds well beyond our local neighbourhood, to systems located at cosmological distances. In order to test thi…
ISO spectroscopy of compact H II regions in the Galaxy. I. The catalogue
Kessler, M. F.; Morisset, C.; Schaerer, D. +9 more
Infrared spectra between 2.3 and 196 µm were taken towards a sample of 45 compact H II regions using the two spectrometers (SWS and LWS) on board ISO. The primary goal is to determine the distribution of element abundances in the Galaxy, although there are also many other uses of this database. The spectra contain a wealth of information on …
An ISO-SWS survey of molecular hydrogen in starburst and Seyfert galaxies
Lutz, D.; Genzel, R.; Rigopoulou, D. +2 more
We present results from a survey of molecular hydrogen emission from a sample of Starburst and Seyfert galaxies carried out with the Infrared Space Observatory (ISO). Pure rotational H2 emission has been detected in a number of extragalactic objects and a variety of environments. A number of transitions from S(7) to S(0) are detected in…
The AGN contribution to mid-infrared surveys. X-ray counterparts of the mid-IR sources in the Lockman Hole and HDF-N
Altieri, B.; Elbaz, D.; Franceschini, A. +5 more
We provide constraints on the AGN contribution to the mid-IR extragalactic background light from a correlation analysis of deep X-ray and mid-IR observations in two regions centred on the Lockman Hole and Hubble Deep Field North (HDF-N). The Lockman region, of more than 200 square arcminutes, was observed by ISOCAM and XMM-Newton to a depth of 0.3…
The carrier of the ``30'' mu m emission feature in evolved stars. A simple model using magnesium sulfide
Waters, L. B. F. M.; Hony, S.; Tielens, A. G. G. M.
We present 2-45 mu m spectra of a large sample of carbon-rich evolved stars in order to study the ``30'' mu m feature. We find the ``30'' mu m feature in a wide range of sources: low mass loss carbon stars, extreme carbon-stars, post-AGB objects and planetary nebulae. We extract the profiles from the sources by using a simple systematic approach t…
ISO spectroscopy of compact H II regions in the Galaxy. II. Ionization and elemental abundances
Kessler, M. F.; Morisset, C.; Schaerer, D. +9 more
Based on the ISO spectral catalogue of compact H II regions by \cite{peeters:catalogue}, we present a first analysis of the hydrogen recombination and atomic fine-structure lines originated in the ionized gas. The sample consists of 34 H II regions located at galactocentric distances between RGal,= 0 and 15 kpc. The SWS H I recombinatio…
Crystalline silicate dust around evolved stars. I. The sample stars
Waters, L. B. F. M.; Barlow, M. J.; Tielens, A. G. G. M. +1 more
This is the first paper in a series of three where we present the first comprehensive inventory of solid state emission bands observed in a sample of 17 oxygen-rich circumstellar dust shells surrounding evolved stars. The data were taken with the Short and Long Wavelength Spectrographs on board of the Infrared Space Observatory (ISO) and cover the…